Core Viewpoint - The article highlights the reflections and remorse of Seiji Shimizu, a former member of the Japanese Imperial Army's Unit 731, regarding the atrocities committed during the war, emphasizing the importance of acknowledging history and promoting peace [4][10]. Group 1: Historical Context - Unit 731 committed unprecedented state-level crimes during the invasion of China, which are memorialized on the "Monument of Apology and Peace" established in 2011 [6]. - Seiji Shimizu, at 95 years old, returned to Harbin, China, to express his remorse and fulfill a long-held wish to apologize to the victims of Unit 731 [4][6]. Group 2: Personal Testimony - Shimizu recounted his experiences as a young soldier in Unit 731, including witnessing horrific acts and being subjected to experiments himself, which have haunted him throughout his life [5][10]. - He described the emotional toll of his past, stating that the memories of the atrocities committed by Unit 731 have caused him nightmares, but his recent trip to China has alleviated some of that suffering [6][10]. Group 3: Advocacy for Peace - Shimizu hopes that his actions will encourage the Japanese government to confront its historical actions and consider official apologies to China [6][10]. - He has been actively participating in peace activities and public speaking engagements to raise awareness about the crimes of Unit 731, despite facing backlash from right-wing factions in Japan [8][9]. Group 4: Educational Impact - Shimizu's testimony has been instrumental in educating younger generations about the realities of Unit 731, which are often omitted from Japanese educational curricula [10]. - His ongoing efforts aim to ensure that the history of Unit 731 is not forgotten and serves as a reminder of the importance of human values and the consequences of war [10].